Work breakdown structure

The standard Worker type has fields for Parent and Sequence which can be used to arrange workers into a hierarchy. This is a hierarchy between workers, and is separate from the containment of workers in groups and of the hierarchy of groups.

Task Script provides methods to getChildren(), getParent() and setChildren() to manage the WBS.  The Task group step type provides an action to visualise the hierarchy as a work breakdown structure, and to maintain it using drag-and-drop actions, effectively turning a group into a project plan.

The work breakdown structure also plays a part in dependency processing, which is described in the next section.